Can't go wrong with any of them. I use 140s in the WSM and 130s in the 270 win. This is just how it ended up accuracy wise. As to the original question of why 130,140 and 150's. Jack O'Conner wrote that the 140's were made for people who can't make up their mind between a 130 and 150. I think he had it right.
I think JOC was probably about right. Hard to argue the pile of animals killed with a 130 grain bullet from a 270 Winchester.
